Heat responsive device



March 7, 1933. A c ROWLEY 1,900,765

HEAT RESPONSIVE DEVICE Filed OCt. 16, 1930 Patented Mar. 7 1933 UNITED "STATES "PATENT OFFICE ARTHUR C. ROWLE'Z OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO GLOBE AUTO- MATIC SPRINKLER COMPANY, PHILADELPHIA, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA I HEAT BESPONSIVE DEVICE Application filed October 16, 1980. Serial No. 489,219.

This invention relates to improvements in heat responsive devices for controlling mechanical movement, and theprincipal object of the invention is to provide a device of the stated character in the form of a unit of simple construction and high operating efficiency which may be readilyattached in installation and detached for replacement.

Another object of the invention is to provide a device of the stated character in which the fusible composition forming a part thereof is in the normal load-supporting function continuously under compression.

Still anotherobject of the invention is to provide a device of the stated character incorporating a novel collapsible locking element having a relatively large contact area with I the active temperature responsive medium. 7

The invention further resides in certain novel structural details and features hereinafter set forth and illustrated inthe attached drawing, in which:

Figure 1 is a sectional view illustrating a heat responsive unit made in accordance with my invention as applied to the control of an electric switch;

Fig. 2 illustrates the unit utilized for the purpose of supporting a load whose release is desired at a predetermined temperature in the surrounding space;

Figs. 3 and 4 are sectional views on the lines 33 and 44, respectively, of Figure 1, and

Figs. 5, 6 and 7 are views in perspective of individual elements of the device.

With reference to the drawing, my device in a preferred embodiment takes the form of a unit comprising a cylindrical casing member 1, see Fig. 5, having a relatively small aperture 2 at one end, and having at the other end an outwardly extending radial flange 3. In conjunction with the casing 1, the unit in the illustrated embodiment comprises a cover element 4, see Fig. 7, which in assembly is adapted to rest against the outer face of the flange 3 and which is provided with transversely projecting lugs 5 adapted to be turned over the edge of the said flange 3, thereby to securely fasten the cover element 4 to the casing. The cover member 4 may also comprise peripheral lugs 6 transversely projecting 1n a direction opposite to the lugs 5, the lugs 6 constituting a means for attaching the unlt to a supporting structure, as hereinafter set forth. It will be noted that the cover 4 has a central aperture 7, and that in the illustrated embodiment the portion of the cover nnmediately surrounding this aperture is coned outwardly.

The unitfurther comprises a stem 8, see F 1g. 1, having at one end a suitably formed head 9;, and cooperating with this stem 8 in assembly, a plurality of segmental retaining elements 10 which as shown in Fig. 6 constltute in effect complementary parts of a c1rcular disk which, as illustrated in Figs. 1 and 1, are adapted to lie within the bottom of the casing 1. The inner or convergin corners of the disks 10 are cut away to a 0rd a central aperture 11 which as illustrated in Fig. 1 is adapted to embrace the stem 8 behind thehead 9, the aperture 11 being smaller in diameter than the corresponding dimension of the head 9, Under these circumstances, the stem 8 cannot be withdrawn from the easlng without angularly displacing the segmental sections 10.

In practice, the interior cavity of the casing 1 surrounding the stem 8 is entirely filled with a suitable fusible composition, such for example as alphamononitronaphthalene, this composition in Fig. 1 being designated by the reference numeral 12. This composition 12 is solid under normal temperatures, and in the solid state rigidly holds the locking elements 10 in the flat position in the bottom of the casing, as illustrated, and thereby prevents'retraction of the stem 8. This stem preferably isformed as illustrated in Fig. 1 with a'reverse shoulder 13 opposite to and sep arated from the inner face of the head 9 by a relatively narrow neck portion 14 which as previously described is embraced bytheretaining elements 10.

In the embodiment-illustrated in Fig. l, the unit describedabove is utilized for controlling an electric switch comprising a pivoted blade 15 and the usual cooperating contact post 16. In the present instance, a spring 17 flange 19 secured to the latter and suitably interlocked or fastened to the lugs 6 of the said unit. The switch panel 20 is apertured at 21 for passage of the stem 8 whichisthreaded into a bifurcated link 21 pivotally secured at 22 to the blade 15. It will be apparent that the blade 15 is retained in the position illustrated against the tension of the spring 17 by means of the fusible composition 12 which retains the locking segments 10 in the operative position with respect to the stem 8, as previously set forth. It will be noted further that the' spring pressure is transmitted through the relatively small head 9 of the stem 8 to the inner edges of the segments 10, and that'the effective bearing between these segments and the fusible composition 12 is a relatively great one alfording considerable mechanical strength to the unit in its-opposition to'the spring action.

In operation, abnormally high temperatures in the surrounding area will result in 7 fusion or melting of the composition 12, which immediately releases the segments 10 and permits them to move inwardly at their inner edges under the tension exerted through the spring 17 uponthe stem, the segments pivot ing about their outer peripheral edges and releasing the stem. Escape of the fused composition is permitted through the conical opening in the cover member 4 surrounding the stem, sufficient clearance between the cover and the stem being provided at this'point to permit free flow of the fused composition.

Following fusion of the composition under abnormally high temperatures, the unit is readily removed and replaced by a fresh unit.

It wil'l benoted that in this unit the composi:

tion 12 is maintained by the load under compression between the cover member 4 and the segmental elements 10.

In Fig. 2, the unit constructed essentially as described above is shown as supporting a weighted lever 22. In this instance, the position of the unit with respect to the load is reversed, the load being applied directly to the'he'ad 9a of the stem, as clearly illustrated.

Fusion of the composition within the casing 1 occurring at apredetermined abnormal temperature permits the stem 9a to move downl-wardly under pressure of the lever 22 and thereby releases the load.

It will be apparent that the device is subject to considerable modification in' structural detail and form without departure from the I claim: I a

1. In a device of the stated character, the combination with a casing, of a releasable load-engaging member, and means within the casing normally preventing said release, said means including a retaining element adapted for displacement from an operative position to release the said member, and a body of fusible composition held under compression "by the load and, normally preventing said displacement. i

2. In a device of the stated character, the combination with a casing having registering openings in opposite sides thereof, a stem extending through said casing and having a restricted portion, a disk in said casing com.- prising'a plurality of segmental elements and having an opening closely embracing said restricted portion of the stem, and a fusible composition normallyimmobilizing the seg- 35 ments of said disk within the casing and thereby anchoring said stem, fusion of said composition permitting movement of said segments releasing the stem from the an- ,i chored position.

8'. In a device of the stated character, the combination with a casing having an opening therein, of an element'movable in said casing and accessible through said opening, said element -having a shoulder, a plate loosely mounted in said casing,,and a fusible composition normally 'retaining'said plate in interlocking engagement with said shoulder to thereby immobilize said element in the cats ing, said plate being displaceable on-fusion of said composition to release the element.

' ARTHU R C. ROWLEY.

inventiomand is applicable to the control of 7 -many different forms of mechanical movement. 

